The aim of this research is to determine whether exposure to narcotic drugs during the perinatal period may affect protein synthesis, enzyme development and neurohormone metabolism in the developing mouse brain. We have found that morphine treatment can increase the levels of acetylcholinesterase and choline acetyltransferase in cell cultures of embryonic chick brain and mouse neuroblastoma but not in adult mice. Pregnant mice will be injected with morphine in order to produce narcotic addiction in their offspring. Baby mice will also be injected. The development of cholinesterase, choline acetyltransferase, glutamate decarboxylase, tyrosine hydroxylase and adenyl cyclase will be measured in the brains of these mice as they mature. The in vivo incorporation of labeled amino acids into different brain proteins will be determined with the aid of acrylamide gel isoelectric focusing. Some of the addicted baby mice will be tested after they grow up for possible changes in response to narcotics, stimulants, barbiturates, ethanol, and phenothiazine tranquilizers. We will also look for changes in the development of tolerance to such drugs in these animals.